This invention relates to equipment for processing of liquids that must be kept aseptic, i.e., pharmaceuticals, dairy products, other food products for human consumption, beauty products, skin care products, and the like. The invention is more particularly concerned with sanitary valves of the type used in the dairy, food processing, and/or pharmaceutical industries, in which the flow of a fluid is to be regulated or diverted from one flow path to another. The invention is more directly concerned with diaphragm valves, that is, valves of the type in which a flexible membrane isolates the mechanical portions of the valve from the flow of fluid. The invention is more specifically concerned with a diaphragm valve of simple design and which can be cleaned and sterilized in place by the flow of a cleaning liquid through the valve. Sanitary diaphragm valves of this type can be used in a milk pasteurization line e.g. as a pressure regulating valve. These valve may also be employed as a drain valve for a sanitary tank to connect the tank to subsequent stage(s) in a processing line.
In order to ensure that the sanitary tank and conduit can be cleansed and sanitized between processes, the processing flow path, including any valves, need to be designed so that all components can be completely cleaned in place of any product by washing it and rinsing it with a cleaning fluid that must reach every point on the interior of the conduit, including every point in the valve cavities. No threaded connectors can be used anywhere that the liquid product flows, because of the difficulty in cleaning the threads. Any threads need to be sealed off and isolated from any contact with the processed fluid. In order to accommodate this requirement, the sanitary valves used in the dairy industry, food processing industries, pharmaceutical industry, have been complex and difficult to repair and maintain, and represent a significant capital expense.